Lawyers for the man suspected of murdering Madeleine McCann say he will refuse to answer questions unless he is shown proof.
He will decline to be quizzed as prosecutors must have proof he was involved in her disappearance, according to a newspaper report.
German investigators believe Christian Brueckner killed Madeleine soon after allegedly abducting her from a holiday apartment in the Portuguese resort of Praia da Luz in May, 2007.
The Times reports today that investigators are also searching for a link connecting Brueckner to an incident involving a 10-year-old British girl in the same resort in 2005.
The incident took place the same year he raped a woman at a villa nearby - a crime for which he was later convicted and jailed.
The newspaper reports police were also aware of nine sexual assaults and three attempts against British girls aged from six to 12 who were holidaying in the area between 2004 and 2006
According to the newspaper, Brueckner's lawyer Friedrich Fulscher said: "Mr B is remaining silent on the allegation at this time on the advice of his defence counsel. This is quite common in criminal proceedings.
"It is the duty of the state to prove that a suspect committed a crime. No accused person has to prove his innocence to the investigating authorities."
Brueckner, 43, is in jail in Germany for drug dealing. He is appealing against a conviction for the 2005 rape.
Asked how Brueckner responds to reports linking him to other cases around Europe, Mr Fulscher said: "We are reviewing every article and will decide on a case-by-case basis whether to take legal action against the media concerned."
Meanwhile, a former German police chief has admitted it was a "huge mistake" to notify Brueckner in 2013 that he was a person of interest in Madeleine's disappearance.
Police in Braunschweig, northern Germany, sent Brueckner a summons letter seven years ago to appear for "questioning" in relation to the "missing persons case Madeleine McCann (crime scene Portugal)", The Daily Telegraph reports.
The move happened before a significant police investigation, and may have allowed Bruckner to destroy any evidence that may have existed, experts told the German newspaper Der Spiegel last week.
Ulf Kuch, the former head of police in the German city of Braunschweig, said sending the letter "was a huge mistake".
Mr Kuch said he did not know about the Brueckner summons despite his role at the time as supervisor for the officer who issued the notice, The Telegraph reported.
Portuguese police are said to be considering searching abandoned wells near a farmhouse rented by Brueckner on the outskirts of Praia da Luz in hope of finding clues into Madeleine's disappearance, The Times says.
Her body has never been found, despite years of desperate searching by detectives and her parents, Kate and Gerry McCann, who had always held hopes of finding her alive.